jquery.roundabout.js

/**
 * jQuery Roundabout - v2.4
 * http://fredhq.com/projects/roundabout
 *
 * Moves list-items of enabled ordered and unordered lists long
 * a chosen path. Includes the default "lazySusan" path, that
 * moves items long a spinning turntable.
 *
 * Terms of Use // jQuery Roundabout
 *
 * Open source under the BSD license
 *
 * Copyright (c) 2011-2012, Fred LeBlanc
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   - Neither the name of the author nor the names of its contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
(function($) {
	"use strict";
	
	var defaults, internalData, methods;

	// add default shape
	$.extend({
		roundaboutShapes: {
			def: "lazySusan",
			lazySusan: function (r, a, t) {
				return {
					x: Math.sin(r + a),
					y: (Math.sin(r + 3 * Math.PI / 2 + a) / 8) * t,
					z: (Math.cos(r + a) + 1) / 2,
					scale: (Math.sin(r + Math.PI / 2 + a) / 2) + 0.5
				};
			}
		}
	});

	defaults = {
		bearing: 0.0,
		tilt: 0.0,
		minZ: 100,
		maxZ: 280,
		minOpacity: 0.4,
		maxOpacity: 1.0,
		minScale: 0.4,
		maxScale: 1.0,
		duration: 600,
		btnNext: null,
		btnNextCallback: function() {},
		btnPrev: null,
		btnPrevCallback: function() {},
		btnToggleAutoplay: null,
		btnStartAutoplay: null,
		btnStopAutoplay: null,
		easing: "swing",
		clickToFocus: true,
		clickToFocusCallback: function() {},
		focusBearing: 0.0,
		shape: "lazySusan",
		debug: false,
		childSelector: "li",
		startingChild: null,
		reflect: false,
		floatComparisonThreshold: 0.001,
		autoplay: false,
		autoplayDuration: 1000,
		autoplayPauseOnHover: false,
		autoplayCallback: function() {},
		autoplayInitialDelay: 0,
		enableDrag: false,
		dropDuration: 600,
		dropEasing: "swing",
		dropAnimateTo: "nearest",
		dropCallback: function() {},
		dragAxis: "x",
		dragFactor: 4,
		triggerFocusEvents: true,
		triggerBlurEvents: true,
		responsive: false
	};

	internalData = {
		autoplayInterval: null,
		autoplayIsRunning: false,
		autoplayStartTimeout: null,
		animating: false,
		childInFocus: -1,
		touchMoveStartPosition: null,
		stopAnimation: false,
		lastAnimationStep: false
	};

	methods = {

		// starters
		// -----------------------------------------------------------------------

		// init
		// starts up roundabout
		init: function(options, callback, relayout) {
			var settings,
			    now = (new Date()).getTime();

			options   = (typeof options === "object") ? options : {};
			callback  = ($.isFunction(callback)) ? callback : function() {};
			callback  = ($.isFunction(options)) ? options : callback;
			settings  = $.extend({}, defaults, options, internalData);

			return this
				.each(function() {
					// make options
					var self = $(this),
					    childCount = self.children(settings.childSelector).length,
					    period = 360.0 / childCount,
					    startingChild = (settings.startingChild && settings.startingChild > (childCount - 1)) ? (childCount - 1) : settings.startingChild,
					    startBearing = (settings.startingChild === null) ? settings.bearing : 360 - (startingChild * period),
					    holderCSSPosition = (self.css("position") !== "static") ? self.css("position") : "relative";

					self
						.css({  // starting styles
							padding:   0,
							position:  holderCSSPosition
						})
						.addClass("roundabout-holder")
						.data(  // starting options
							"roundabout",
							$.extend(
								{},
								settings,
								{
									startingChild: startingChild,
									bearing: startBearing,
									oppositeOfFocusBearing: methods.normalize.apply(null, [settings.focusBearing - 180]),
									dragBearing: startBearing,
									period: period
								}
							)
						);

					// unbind any events that we set if we're relaying out
					if (relayout) {
						self
							.unbind(".roundabout")
							.children(settings.childSelector)
								.unbind(".roundabout");
					} else {
						// bind responsive action
						if (settings.responsive) {
							$(window).bind("resize", function() {
								methods.relayoutChildren.apply(self);
							});
						}
					}

					// bind click-to-focus
					if (settings.clickToFocus) {
						self
							.children(settings.childSelector)
							.each(function(i) {
								$(this)
									.bind("click.roundabout", function() {
										var degrees = methods.getPlacement.apply(self, [i]);

										if (!methods.isInFocus.apply(self, [degrees])) {
											methods.stopAnimation.apply($(this));
											if (!self.data("roundabout").animating) {
												methods.animateBearingToFocus.apply(self, [degrees, self.data("roundabout").clickToFocusCallback]);
											}
											return false;
										}
									});
							});
					}

					// bind next buttons
					if (settings.btnNext) {
						$(settings.btnNext)
							.bind("click.roundabout", function() {
								if (!self.data("roundabout").animating) {
									methods.animateToNextChild.apply(self, [self.data("roundabout").btnNextCallback]);
								}
								return false;
							});
					}

					// bind previous buttons
					if (settings.btnPrev) {
						$(settings.btnPrev)
							.bind("click.roundabout", function() {
								methods.animateToPreviousChild.apply(self, [self.data("roundabout").btnPrevCallback]);
								return false;
							});
					}

					// bind toggle autoplay buttons
					if (settings.btnToggleAutoplay) {
						$(settings.btnToggleAutoplay)
							.bind("click.roundabout", function() {
								methods.toggleAutoplay.apply(self);
								return false;
							});
					}

					// bind start autoplay buttons
					if (settings.btnStartAutoplay) {
						$(settings.btnStartAutoplay)
							.bind("click.roundabout", function() {
								methods.startAutoplay.apply(self);
								return false;
							});
					}

					// bind stop autoplay buttons
					if (settings.btnStopAutoplay) {
						$(settings.btnStopAutoplay)
							.bind("click.roundabout", function() {
								methods.stopAutoplay.apply(self);
								return false;
							});
					}

					// autoplay pause on hover
					if (settings.autoplayPauseOnHover) {
						self
							.bind("mouseenter.roundabout.autoplay", function() {
								methods.stopAutoplay.apply(self, [true]);
							})
							.bind("mouseleave.roundabout.autoplay", function() {
								methods.startAutoplay.apply(self);
							});
					}

					// drag and drop
					if (settings.enableDrag) {
						// on screen
						if (!$.isFunction(self.drag)) {
							if (settings.debug) {
								alert("You do not have the drag plugin loaded.");
							}
						} else if (!$.isFunction(self.drop)) {
							if (settings.debug) {
								alert("You do not have the drop plugin loaded.");
							}
						} else {
							self
								.drag(function(e, properties) {
									var data = self.data("roundabout"),
									    delta = (data.dragAxis.toLowerCase() === "x") ? "deltaX" : "deltaY";
									methods.stopAnimation.apply(self);
									methods.setBearing.apply(self, [data.dragBearing + properties[delta] / data.dragFactor]);
								})
								.drop(function(e) {
									var data = self.data("roundabout"),
									    method = methods.getAnimateToMethod(data.dropAnimateTo);
									methods.allowAnimation.apply(self);
									methods[method].apply(self, [data.dropDuration, data.dropEasing, data.dropCallback]);
									data.dragBearing = data.period * methods.getNearestChild.apply(self);
								});
						}

						// on mobile
						self
							.each(function() {
								var element = $(this).get(0),
								    data = $(this).data("roundabout"),
								    page = (data.dragAxis.toLowerCase() === "x") ? "pageX" : "pageY",
								    method = methods.getAnimateToMethod(data.dropAnimateTo);

								// some versions of IE don't like this
								if (element.addEventListener) {
									element.addEventListener("touchstart", function(e) {
										data.touchMoveStartPosition = e.touches[0][page];
									}, false);

									element.addEventListener("touchmove", function(e) {
										var delta = (e.touches[0][page] - data.touchMoveStartPosition) / data.dragFactor;
										e.preventDefault();
										methods.stopAnimation.apply($(this));
										methods.setBearing.apply($(this), [data.dragBearing + delta]);
									}, false);

									element.addEventListener("touchend", function(e) {
										e.preventDefault();
										methods.allowAnimation.apply($(this));
										method = methods.getAnimateToMethod(data.dropAnimateTo);
										methods[method].apply($(this), [data.dropDuration, data.dropEasing, data.dropCallback]);
										data.dragBearing = data.period * methods.getNearestChild.apply($(this));
									}, false);
								}
							});
					}

					// start children
					methods.initChildren.apply(self, [callback, relayout]);
				});
		},


		// initChildren
		// applys settings to child elements, starts roundabout
		initChildren: function(callback, relayout) {
			var self = $(this),
			    data = self.data("roundabout");

			callback = callback || function() {};
			
			self.children(data.childSelector).each(function(i) {
				var startWidth, startHeight, startFontSize,
				    degrees = methods.getPlacement.apply(self, [i]);

				// on relayout, grab these values from current data
				if (relayout && $(this).data("roundabout")) {
					startWidth = $(this).data("roundabout").startWidth;
					startHeight = $(this).data("roundabout").startHeight;
					startFontSize = $(this).data("roundabout").startFontSize;
				}

				// apply classes and css first
				$(this)
					.addClass("roundabout-moveable-item")
					.css("position", "absolute");

				// now measure
				$(this)
					.data(
						"roundabout",
						{
							startWidth: startWidth || $(this).width(),
							startHeight: startHeight || $(this).height(),
							startFontSize: startFontSize || parseInt($(this).css("font-size"), 10),
							degrees: degrees,
							backDegrees: methods.normalize.apply(null, [degrees - 180]),
							childNumber: i,
							currentScale: 1,
							parent: self
						}
					);
			});

			methods.updateChildren.apply(self);

			// start autoplay if necessary
			if (data.autoplay) {
				data.autoplayStartTimeout = setTimeout(function() {
					methods.startAutoplay.apply(self);
				}, data.autoplayInitialDelay);
			}

			self.trigger('ready');
			callback.apply(self);
			return self;
		},



		// positioning
		// -----------------------------------------------------------------------

		// updateChildren
		// move children elements into their proper locations
		updateChildren: function() {
			return this
				.each(function() {
					var self = $(this),
					    data = self.data("roundabout"),
					    inFocus = -1,
					    info = {
							bearing: data.bearing,
							tilt: data.tilt,
							stage: {
								width: Math.floor($(this).width() * 0.9),
								height: Math.floor($(this).height() * 0.9)
							},
							animating: data.animating,
							inFocus: data.childInFocus,
							focusBearingRadian: methods.degToRad.apply(null, [data.focusBearing]),
							shape: $.roundaboutShapes[data.shape] || $.roundaboutShapes[$.roundaboutShapes.def]
					    };

					// calculations
					info.midStage = {
						width: info.stage.width / 2,
						height: info.stage.height / 2
					};

					info.nudge = {
						width: info.midStage.width + (info.stage.width * 0.05),
						height: info.midStage.height + (info.stage.height * 0.05)
					};

					info.zValues = {
						min: data.minZ,
						max: data.maxZ,
						diff: data.maxZ - data.minZ
					};

					info.opacity = {
						min: data.minOpacity,
						max: data.maxOpacity,
						diff: data.maxOpacity - data.minOpacity
					};

					info.scale = {
						min: data.minScale,
						max: data.maxScale,
						diff: data.maxScale - data.minScale
					};

					// update child positions
					self.children(data.childSelector)
						.each(function(i) {
							if (methods.updateChild.apply(self, [$(this), info, i, function() { $(this).trigger('ready'); }]) && (!info.animating || data.lastAnimationStep)) {
								inFocus = i;
								$(this).addClass("roundabout-in-focus");
							} else {
								$(this).removeClass("roundabout-in-focus");
							}
						});

					if (inFocus !== info.inFocus) {
						// blur old child
						if (data.triggerBlurEvents) {
							self.children(data.childSelector)
								.eq(info.inFocus)
									.trigger("blur");
						}

						data.childInFocus = inFocus;

						if (data.triggerFocusEvents && inFocus !== -1) {
							// focus new child
							self.children(data.childSelector)
								.eq(inFocus)
									.trigger("focus");
						}
					}

					self.trigger("childrenUpdated");
				});
		},


		// updateChild
		// repositions a child element into its new position
		updateChild: function(childElement, info, childPos, callback) {
			var factors,
			    self = this,
			    child = $(childElement),
			    data = child.data("roundabout"),
			    out = [],
			    rad = methods.degToRad.apply(null, [(360.0 - data.degrees) + info.bearing]);

			callback = callback || function() {};

			// adjust radians to be between 0 and Math.PI * 2
			rad = methods.normalizeRad.apply(null, [rad]);

			// get factors from shape
			factors = info.shape(rad, info.focusBearingRadian, info.tilt);

			// correct
			factors.scale = (factors.scale > 1) ? 1 : factors.scale;
			factors.adjustedScale = (info.scale.min + (info.scale.diff * factors.scale)).toFixed(4);
			factors.width = (factors.adjustedScale * data.startWidth).toFixed(4);
			factors.height = (factors.adjustedScale * data.startHeight).toFixed(4);

			// update item
			child
				.css({
					left: ((factors.x * info.midStage.width + info.nudge.width) - factors.width / 2.0).toFixed(0) + "px",
					top: ((factors.y * info.midStage.height + info.nudge.height) - factors.height / 2.0).toFixed(0) + "px",
					width: factors.width + "px",
					height: factors.height + "px",
					opacity: (info.opacity.min + (info.opacity.diff * factors.scale)).toFixed(2),
					zIndex: Math.round(info.zValues.min + (info.zValues.diff * factors.z)),
					fontSize: (factors.adjustedScale * data.startFontSize).toFixed(1) + "px"
				});
			data.currentScale = factors.adjustedScale;

			// for debugging purposes
			if (self.data("roundabout").debug) {
				out.push("<div style=\"font-weight: normal; font-size: 10px; padding: 2px; width: " + child.css("width") + "; background-color: #ffc;\">");
				out.push("<strong style=\"font-size: 12px; white-space: nowrap;\">Child " + childPos + "</strong><br />");
				out.push("<strong>left:</strong> " + child.css("left") + "<br />");
				out.push("<strong>top:</strong> " + child.css("top") + "<br />");
				out.push("<strong>width:</strong> " + child.css("width") + "<br />");
				out.push("<strong>opacity:</strong> " + child.css("opacity") + "<br />");
				out.push("<strong>height:</strong> " + child.css("height") + "<br />");
				out.push("<strong>z-index:</strong> " + child.css("z-index") + "<br />");
				out.push("<strong>font-size:</strong> " + child.css("font-size") + "<br />");
				out.push("<strong>scale:</strong> " + child.data("roundabout").currentScale);
				out.push("</div>");

				child.html(out.join(""));
			}

			// trigger event
			child.trigger("reposition");
			
			// callback
			callback.apply(self);

			return methods.isInFocus.apply(self, [data.degrees]);
		},



		// manipulation
		// -----------------------------------------------------------------------

		// setBearing
		// changes the bearing of the roundabout
		setBearing: function(bearing, callback) {
			callback = callback || function() {};
			bearing = methods.normalize.apply(null, [bearing]);

			this
				.each(function() {
					var diff, lowerValue, higherValue,
					    self = $(this),
					    data = self.data("roundabout"),
					    oldBearing = data.bearing;

					// set bearing
					data.bearing = bearing;
					self.trigger("bearingSet");
					methods.updateChildren.apply(self);

					// not animating? we're done here
					diff = Math.abs(oldBearing - bearing);
					if (!data.animating || diff > 180) {
						return;
					}

					// check to see if any of the children went through the back
					diff = Math.abs(oldBearing - bearing);
					self.children(data.childSelector).each(function(i) {
						var eventType;

						if (methods.isChildBackDegreesBetween.apply($(this), [bearing, oldBearing])) {
							eventType = (oldBearing > bearing) ? "Clockwise" : "Counterclockwise";
							$(this).trigger("move" + eventType + "ThroughBack");
						}
					});
				});

			// call callback if one was given
			callback.apply(this);
			return this;
		},


		// adjustBearing
		// change the bearing of the roundabout by a given degree
		adjustBearing: function(delta, callback) {
			callback = callback || function() {};
			if (delta === 0) {
				return this;
			}

			this
				.each(function() {
					methods.setBearing.apply($(this), [$(this).data("roundabout").bearing + delta]);
				});

			callback.apply(this);
			return this;
		},


		// setTilt
		// changes the tilt of the roundabout
		setTilt: function(tilt, callback) {
			callback = callback || function() {};

			this
				.each(function() {
					$(this).data("roundabout").tilt = tilt;
					methods.updateChildren.apply($(this));
				});

			// call callback if one was given
			callback.apply(this);
			return this;
		},


		// adjustTilt
		// changes the tilt of the roundabout
		adjustTilt: function(delta, callback) {
			callback = callback || function() {};

			this
				.each(function() {
					methods.setTilt.apply($(this), [$(this).data("roundabout").tilt + delta]);
				});

			callback.apply(this);
			return this;
		},



		// animation
		// -----------------------------------------------------------------------

		// animateToBearing
		// animates the roundabout to a given bearing, all animations come through here
		animateToBearing: function(bearing, duration, easing, passedData, callback) {
			var now = (new Date()).getTime();

			callback = callback || function() {};

			// find callback function in arguments
			if ($.isFunction(passedData)) {
				callback = passedData;
				passedData = null;
			} else if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			this
				.each(function() {
					var timer, easingFn, newBearing,
					    self = $(this),
					    data = self.data("roundabout"),
					    thisDuration = (!duration) ? data.duration : duration,
					    thisEasingType = (easing) ? easing : data.easing || "swing";

					// is this your first time?
					if (!passedData) {
						passedData = {
							timerStart: now,
							start: data.bearing,
							totalTime: thisDuration
						};
					}

					// update the timer
					timer = now - passedData.timerStart;

					if (data.stopAnimation) {
						methods.allowAnimation.apply(self);
						data.animating = false;
						return;
					}

					// we need to animate more
					if (timer < thisDuration) {
						if (!data.animating) {
							self.trigger("animationStart");
						}

						data.animating = true;

						if (typeof $.easing.def === "string") {
							easingFn = $.easing[thisEasingType] || $.easing[$.easing.def];
							newBearing = easingFn(null, timer, passedData.start, bearing - passedData.start, passedData.totalTime);
						} else {
							newBearing = $.easing[thisEasingType]((timer / passedData.totalTime), timer, passedData.start, bearing - passedData.start, passedData.totalTime);
						}

						// fixes issue #24, animation changed as of jQuery 1.7.2
						if (methods.compareVersions.apply(null, [$().jquery, "1.7.2"]) >= 0) {
							newBearing = passedData.start + ((bearing - passedData.start) * newBearing);
						}

						newBearing = methods.normalize.apply(null, [newBearing]);
						data.dragBearing = newBearing;

						methods.setBearing.apply(self, [newBearing, function() {
							setTimeout(function() {  // done with a timeout so that each step is displayed
								methods.animateToBearing.apply(self, [bearing, thisDuration, thisEasingType, passedData, callback]);
							}, 0);
						}]);

					// we're done animating
					} else {
						data.lastAnimationStep = true;

						bearing = methods.normalize.apply(null, [bearing]);
						methods.setBearing.apply(self, [bearing, function() {
							self.trigger("animationEnd");
						}]);
						data.animating = false;
						data.lastAnimationStep = false;
						data.dragBearing = bearing;

						callback.apply(self);
					}
				});

			return this;
		},


		// animateToNearbyChild
		// animates roundabout to a nearby child
		animateToNearbyChild: function(passedArgs, which) {
			var duration = passedArgs[0],
			    easing = passedArgs[1],
			    callback = passedArgs[2] || function() {};

			// find callback
			if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			return this
				.each(function() {
					var j, range,
					    self = $(this),
					    data = self.data("roundabout"),
					    bearing = (!data.reflect) ? data.bearing % 360 : data.bearing,
					    length = self.children(data.childSelector).length;

					if (!data.animating) {
						// reflecting, not moving to previous || not reflecting, moving to next
						if ((data.reflect && which === "previous") || (!data.reflect && which === "next")) {
							// slightly adjust for rounding issues
							bearing = (Math.abs(bearing) < data.floatComparisonThreshold) ? 360 : bearing;

							// clockwise
							for (j = 0; j < length; j += 1) {
								range = {
									lower: (data.period * j),
									upper: (data.period * (j + 1))
								};
								range.upper = (j === length - 1) ? 360 : range.upper;

								if (bearing <= Math.ceil(range.upper) && bearing >= Math.floor(range.lower)) {
									if (length === 2 && bearing === 360) {
										methods.animateToDelta.apply(self, [-180, duration, easing, callback]);
									} else {
										methods.animateBearingToFocus.apply(self, [range.lower, duration, easing, callback]);
									}
									break;
								}
							}
						} else {
							// slightly adjust for rounding issues
							bearing = (Math.abs(bearing) < data.floatComparisonThreshold || 360 - Math.abs(bearing) < data.floatComparisonThreshold) ? 0 : bearing;

							// counterclockwise
							for (j = length - 1; j >= 0; j -= 1) {
								range = {
									lower: data.period * j,
									upper: data.period * (j + 1)
								};
								range.upper = (j === length - 1) ? 360 : range.upper;

								if (bearing >= Math.floor(range.lower) && bearing < Math.ceil(range.upper)) {
									if (length === 2 && bearing === 360) {
										methods.animateToDelta.apply(self, [180, duration, easing, callback]);
									} else {
										methods.animateBearingToFocus.apply(self, [range.upper, duration, easing, callback]);
									}
									break;
								}
							}
						}
					}
				});
		},


		// animateToNearestChild
		// animates roundabout to the nearest child
		animateToNearestChild: function(duration, easing, callback) {
			callback = callback || function() {};

			// find callback
			if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			return this
				.each(function() {
					var nearest = methods.getNearestChild.apply($(this));
					methods.animateToChild.apply($(this), [nearest, duration, easing, callback]);
				});
		},


		// animateToChild
		// animates roundabout to a given child position
		animateToChild: function(childPosition, duration, easing, callback) {
			callback = callback || function() {};

			// find callback
			if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			return this
				.each(function() {
					var child,
					    self = $(this),
					    data = self.data("roundabout");

					if (data.childInFocus !== childPosition && !data.animating) {
						child = self.children(data.childSelector).eq(childPosition);
						methods.animateBearingToFocus.apply(self, [child.data("roundabout").degrees, duration, easing, callback]);
					}
				});
		},


		// animateToNextChild
		// animates roundabout to the next child
		animateToNextChild: function(duration, easing, callback) {
			return methods.animateToNearbyChild.apply(this, [arguments, "next"]);
		},


		// animateToPreviousChild
		// animates roundabout to the preious child
		animateToPreviousChild: function(duration, easing, callback) {
			return methods.animateToNearbyChild.apply(this, [arguments, "previous"]);
		},


		// animateToDelta
		// animates roundabout to a given delta (in degrees)
		animateToDelta: function(degrees, duration, easing, callback) {
			callback = callback || function() {};

			// find callback
			if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			return this
				.each(function() {
					var delta = $(this).data("roundabout").bearing + degrees;
					methods.animateToBearing.apply($(this), [delta, duration, easing, callback]);
				});
		},


		// animateBearingToFocus
		// animates roundabout to bring a given angle into focus
		animateBearingToFocus: function(degrees, duration, easing, callback) {
			callback = callback || function() {};

			// find callback
			if ($.isFunction(easing)) {
				callback = easing;
				easing = null;
			} else if ($.isFunction(duration)) {
				callback = duration;
				duration = null;
			}

			return this
				.each(function() {
					var delta = $(this).data("roundabout").bearing - degrees;
					delta = (Math.abs(360 - delta) < Math.abs(delta)) ? 360 - delta : -delta;
					delta = (delta > 180) ? -(360 - delta) : delta;

					if (delta !== 0) {
						methods.animateToDelta.apply($(this), [delta, duration, easing, callback]);
					}
				});
		},


		// stopAnimation
		// if an animation is currently in progress, stop it
		stopAnimation: function() {
			return this
				.each(function() {
					$(this).data("roundabout").stopAnimation = true;
				});
		},


		// allowAnimation
		// clears the stop-animation hold placed by stopAnimation
		allowAnimation: function() {
			return this
				.each(function() {
					$(this).data("roundabout").stopAnimation = false;
				});
		},



		// autoplay
		// -----------------------------------------------------------------------

		// startAutoplay
		// starts autoplaying this roundabout
		startAutoplay: function(callback) {
			return this
				.each(function() {
					var self = $(this),
					    data = self.data("roundabout");

					callback = callback || data.autoplayCallback || function() {};

					clearInterval(data.autoplayInterval);
					data.autoplayInterval = setInterval(function() {
						methods.animateToNextChild.apply(self, [callback]);
					}, data.autoplayDuration);
					data.autoplayIsRunning = true;
					
					self.trigger("autoplayStart");
				});
		},


		// stopAutoplay
		// stops autoplaying this roundabout
		stopAutoplay: function(keepAutoplayBindings) {
			return this
				.each(function() {
					clearInterval($(this).data("roundabout").autoplayInterval);
					$(this).data("roundabout").autoplayInterval = null;
					$(this).data("roundabout").autoplayIsRunning = false;
					
					// this will prevent autoplayPauseOnHover from restarting autoplay
					if (!keepAutoplayBindings) {
						$(this).unbind(".autoplay");
					}
					
					$(this).trigger("autoplayStop");
				});
		},
		
		
		// toggleAutoplay
		// toggles autoplay pause/resume
		toggleAutoplay: function(callback) {
			return this
				.each(function() {
					var self = $(this),
					    data = self.data("roundabout");

					callback = callback || data.autoplayCallback || function() {};

					if (!methods.isAutoplaying.apply($(this))) {
						methods.startAutoplay.apply($(this), [callback]);
					} else {
						methods.stopAutoplay.apply($(this), [callback]);
					}
				});
		},


		// isAutoplaying
		// is this roundabout currently autoplaying?
		isAutoplaying: function() {
			return (this.data("roundabout").autoplayIsRunning);
		},


		// changeAutoplayDuration
		// stops the autoplay, changes the duration, restarts autoplay
		changeAutoplayDuration: function(duration) {
			return this
				.each(function() {
					var self = $(this),
					    data = self.data("roundabout");

					data.autoplayDuration = duration;

					if (methods.isAutoplaying.apply(self)) {
						methods.stopAutoplay.apply(self);
						setTimeout(function() {
							methods.startAutoplay.apply(self);
						}, 10);
					}
				});
		},



		// helpers
		// -----------------------------------------------------------------------

		// normalize
		// regulates degrees to be >= 0.0 and < 360
		normalize: function(degrees) {
			var inRange = degrees % 360.0;
			return (inRange < 0) ? 360 + inRange : inRange;
		},


		// normalizeRad
		// regulates radians to be >= 0 and < Math.PI * 2
		normalizeRad: function(radians) {
			while (radians < 0) {
				radians += (Math.PI * 2);
			}

			while (radians > (Math.PI * 2)) {
				radians -= (Math.PI * 2);
			}

			return radians;
		},


		// isChildBackDegreesBetween
		// checks that a given child's backDegrees is between two values
		isChildBackDegreesBetween: function(value1, value2) {
			var backDegrees = $(this).data("roundabout").backDegrees;

			if (value1 > value2) {
				return (backDegrees >= value2 && backDegrees < value1);
			} else {
				return (backDegrees < value2 && backDegrees >= value1);
			}
		},


		// getAnimateToMethod
		// takes a user-entered option and maps it to an animation method
		getAnimateToMethod: function(effect) {
			effect = effect.toLowerCase();

			if (effect === "next") {
				return "animateToNextChild";
			} else if (effect === "previous") {
				return "animateToPreviousChild";
			}

			// default selection
			return "animateToNearestChild";
		},
		
		
		// relayoutChildren
		// lays out children again with new contextual information
		relayoutChildren: function() {
			return this
				.each(function() {
					var self = $(this),
					    settings = $.extend({}, self.data("roundabout"));

					settings.startingChild = self.data("roundabout").childInFocus;
					methods.init.apply(self, [settings, null, true]);
				});
		},


		// getNearestChild
		// gets the nearest child from the current bearing
		getNearestChild: function() {
			var self = $(this),
			    data = self.data("roundabout"),
			    length = self.children(data.childSelector).length;

			if (!data.reflect) {
				return ((length) - (Math.round(data.bearing / data.period) % length)) % length;
			} else {
				return (Math.round(data.bearing / data.period) % length);
			}
		},


		// degToRad
		// converts degrees to radians
		degToRad: function(degrees) {
			return methods.normalize.apply(null, [degrees]) * Math.PI / 180.0;
		},


		// getPlacement
		// returns the starting degree for a given child
		getPlacement: function(child) {
			var data = this.data("roundabout");
			return (!data.reflect) ? 360.0 - (data.period * child) : data.period * child;
		},


		// isInFocus
		// is this roundabout currently in focus?
		isInFocus: function(degrees) {
			var diff,
			    self = this,
			    data = self.data("roundabout"),
			    bearing = methods.normalize.apply(null, [data.bearing]);

			degrees = methods.normalize.apply(null, [degrees]);
			diff = Math.abs(bearing - degrees);

			// this calculation gives a bit of room for javascript float rounding
			// errors, it looks on both 0deg and 360deg ends of the spectrum
			return (diff <= data.floatComparisonThreshold || diff >= 360 - data.floatComparisonThreshold);
		},
		
		
		// getChildInFocus
		// returns the current child in focus, or false if none are in focus
		getChildInFocus: function() {
			var data = $(this).data("roundabout");
			
			return (data.childInFocus > -1) ? data.childInFocus : false;
		},


		// compareVersions
		// compares a given version string with another
		compareVersions: function(baseVersion, compareVersion) {
			var i,
			    base = baseVersion.split(/\./i),
			    compare = compareVersion.split(/\./i),
			    maxVersionSegmentLength = (base.length > compare.length) ? base.length : compare.length;

			for (i = 0; i <= maxVersionSegmentLength; i++) {
				if (base[i] && !compare[i] && parseInt(base[i], 10) !== 0) {
					// base is higher
					return 1;
				} else if (compare[i] && !base[i] && parseInt(compare[i], 10) !== 0) {
					// compare is higher
					return -1;
				} else if (base[i] === compare[i]) {
					// these are the same, next
					continue;
				}

				if (base[i] && compare[i]) {
					if (parseInt(base[i], 10) > parseInt(compare[i], 10)) {
						// base is higher
						return 1;
					} else {
						// compare is higher
						return -1;
					}
				}
			}

			// nothing was triggered, versions are the same
			return 0;
		}
	};


	// start the plugin
	$.fn.roundabout = function(method) {
		if (methods[method]) {
			return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
		} else if (typeof method === "object" || $.isFunction(method) || !method) {
			return methods.init.apply(this, arguments);
		} else {
			$.error("Method " + method + " does not exist for jQuery.roundabout.");
		}
	};
})(jQuery);